HIV neuropathogenesis related to exosomes containing HIV non-coding RNAs

 描述（由申请人提供）：尽管有足够的cART和血液中良好的病毒学控制，但近三分之一的HIV感染者仍会出现神经认知缺陷。这一系列的神经认知缺陷统称为HIV-1相关的神经认知障碍（HAND）。病毒也可能在感染的后期阶段再次进入大脑，此时存在普遍的免疫失败。病毒复制的能力取决于细胞类型及其激活状态。一旦进入脑实质，它就存在于血管周围的巨噬细胞和小胶质细胞中，这些细胞为HIV提供了生产性复制和进化的场所。最近的研究表明，脑膜中也有大量的病毒载量，其中有大量的巨噬细胞。在这些区域内，HIV感染最常位于血管周围区域的巨噬细胞/小胶质细胞和星形胶质细胞，它们构成血脑屏障。血管周围和脑膜巨噬细胞已被证明是活跃的病毒复制在人脑中的网站。外泌体是由多种细胞产生的膜结合囊泡，其含有经典的膜标记蛋白，如四跨膜蛋白、粘附蛋白和金属蛋白酶。它们被认为通过靶细胞摄取或通过膜受体诱导细胞信号传导在细胞间通讯中起重要作用。除了膜蛋白外，外泌体还携带mRNA以及非编码RNA，包括被认为影响靶细胞中基因调控的miRNA。我们小组和其他人的研究表明，HIV-1感染的细胞产生外泌体，通过称为TAR的dsRNA激活幼稚靶细胞。我们的长期目标是了解来自HIV-1感染细胞的外泌体在调节宿主-病毒相互作用中所起的作用。我们假设感染细胞外泌体中存在的独特病毒RNA将改变受体细胞，影响基因表达的调控和炎症反应的建立。我们的目标包括：表征来自cART下受感染供体细胞的外来体的生物起源和功能（目的I）;表征来自用抑制剂处理的受感染细胞的外来体及其细胞来源（目的II），并定义TAR对受体细胞中TLR调节和细胞因子产生的作用机制。总的来说，我们的数据表明，在cART下感染的细胞仍然分泌TAR相关的外泌体，并且这些外泌体激活幼稚的受体细胞，导致不需要的促炎信号。这些活性将通过使用抑制剂逆转，并在体外BBB模型和HIV感染的人源化潜伏模型中进行测试。

 DESCRIPTION (provided by applicant): Nearly one third of HIV-infected individuals develop neurocognitive deficits despite adequate cART and excellent virological control in the blood. This range of neurocognitive deficits is collectively referred to as HIV-1-associated neurocognitive disorders (HAND). Virus may also enter the brain again in the later stages of infection when there is a general immune failure. The ability of the virus to replicate depends on the cell type and its state of activation. Once inside the brain parenchyma, it resides in perivascular macrophages and microglial cells that provide the site of productive replication and evolution for HIV. Recent studies suggest that there is a substantial viral load in the meninges as well where there is a rich collection of macrophages. Within these regions, HIV infects the macrophages/microglia and astrocytes most commonly located in the perivascular regions where they constitute the blood-brain barrier. Perivascular and meningeal macrophages have been shown to be sites of active viral replication in the human brain. Exosomes are membrane-bound vesicles produced by a variety of cells that contain classical membrane marker proteins such as tetraspanins, adhesion proteins and metalloproteinases. They are considered to play an important role in intercellular communication either by target cell uptake or by inducing cell signaling via membrane receptors. In addition to membrane proteins, exosomes carry mRNAs as well as non-coding RNAs, including miRNAs that are thought to affect gene regulation in the target cells. Research by our group and others has shown that HIV-1-infected cells produce exosomes that activate naïve target cells through a dsRNA called TAR. Our long term goal is to understand the role played by exosomes originating from HIV-1 infected cells in regulating host-virus interactions. We hypothesize that unique viral RNA present in the exosomes of infected cells will alter recipient cells impacting regulation of gene expression and establishment of inflammatory response. Our aims include: To characterize the biogenesis and function of exosomes from infected donor cells under cART (Aim I); To characterize exosomes from infected cells treated with inhibitors and their cellular origin (Aim II), and defining the mechanim of TAR effect on TLR modulation and cytokine production in recipient cells. Collectively our data indicates that infected cells under cART still secrete TAR associated exosmes and that these exosomes activate the naïve recipient cells resulting in unwanted proinflammatory signals. These activities will be reversed with use of inhibitors and tested in both an in vitro BBB model and humanized latent model of HIV infection.